Art of manufacturing front forks of cycles



G. s. LEwgs. ART 0F MANUFACTURING FRONT FORKS 0F CYCLES.

APPLICATION FILED' OCT- 4| |920.

Patented Jam. l0, i922 entre@ sraras PATENT @.FFHQE.

GEORGE S. CEXTS, CF OAK PARK, ELLINOIS, ASSIG'NOR TO MEAD CYCLE COMPANY.

ART OF MANUFACTURING FRONT FORKS 0F CYCLES.

recaen?.

Application led October 4, 1920. Serial No. 414,558.

To all whom it may concer/'1b.'

Be it known Ithat l, GEORGE S. LEWIS, a citizen of the United States,residing at Oak Park, in the countyV of Cook and lState of lillinoishave invented a new and useful Improvement in the Art of ManufacturingFront Forks of Cycles, of which the follow ing is a specification.

My invention relates mo-re particularly to front forks of the typeinvolving a crown portion containing an opening in which the upwardlyextending stem of the fork is secured, commonly by brazing it inposition.

It is common practice in the manufacture of forks of this type, toprovide the stem portion referred to, of a piece of steel tubing, and byreason of the extra stress to which it fis subjected adjacent the upperportion of the crown, and in order to economize vas much as possible inthe use ofmaterial, to4

. these tubesy as provided in practice, 'is not uniform, therebeingsuicient variance between the internal dia-meters .of the tubing so thatin many cases the reenforcing insertsprovided, do not'fit the tubes`sufficiently inserts to the tubes.

tightly to insure the roper brazing of the n fact in practice it isoftentimes found that the greater portion of the insert remains unbrazedto the tube, after the brazing operation, thus causingv the fork to lackthe desired resistance to distortion and impairment, at this point.

The object of my present invention is to provide a forkcrown of thegeneral type above referred to and employing a reenforcing insert, whichshall -not present the objections as above pointed out, therebyIinsuring proper strength and rigidity of structure.

Referring to the accompanying drawing :fz

Figure 1 is a view in elevation of a front fork of a' bicycle, producedin accordance with my winvention, certain parts 'of the' structure beingbroken laway and 'a portion thereof being shown in section; and Figure2, a section taken at the line 2-2 on Fig. l and viewed in the directionof the arrows.

The st em portion of the fork is represented a.t`"3, this stem beingshown as rising from a fork crown represented at 4 to which the upperends of the arms 5 of the crown are secured, these arms 5,in accordancewith common practice being adapted to receive at their lower ends .theaxle of the wheel, to be mounted therein. The fork crown 4 is shown asan open-work structure, affording the opening 6 extending therethrough,this being a common form of crown, but it will be understood thattheinvention may be employed in connection with other constructions of`crowns. The stem 3 isformed of a tube 7, shown as cylindrical andpreferably of steel, such as is commonly used in structures of thischaracter and a reenforcing insert ,8'secured in the lower end of thetube 7, the lower end of the stem thus provided extending into theopening 6 in the crown 4.

Specification of Letters VPatent. Patented Jam. 310%, 1922.

The reenforcing insert 8, may be of anysuitable construction, butpreferably of steel, formed, as by drawing it, from a sheet of metal,the shape of this insert being preferablythat shown, Viz., cylindrical,adapting it to conform to the inner cylindrical surfa-ce of the tube 7and with its wall of de- 'creasing thickness from its lower toward .its

upper end, its inner surface flaring upwardly andoutwardly as shown. Themember 8 thusl formed presents a lower end 9 closed, except for thethreaded opening l0 therein which preferably is provided for receiving'ascrew (not shown) for holding a mud-guard in place. In the manufactureof the construction the tube 7 is heated, preferably toV a cherry redcolor, to causait to expand, and

the insert 8 then introduced into the lower end of the. tube to theposition shown in Fig.

1, the tube 7 in cooling shrinking about the member 8 and 'forming atight fit between.

these parts. The stem portion 3 thus formed is then inserted into theopening 6 in the crown 4 to the position shown in Fig. 1, and with thearms 5 of the fork assembled with the crown 4 to the position shown,then subjected to a brazing operation, by plunging the structure into abath of the desirable molten metal, in accordance with common clesformed oa fork crown with a stem porpractice to submerge the jointsbetween the members forming the stem 3 and the joints between the crownand the parts assembled.

therewith as stated. The threaded opening 10 is then preferably formedin the portion 9 and the upper end of the stem 3 threaded-as indicatedat 11.

' It will be understood from the foregoing that inasmuch as the tube 7,is shrunk upon ment of the minimum amount of metal, for

producing a structure presenting the desired resista-nce to stressesthroughout its extent.

'While I have illustrated and described a particular embodiment of myinvention and have explainedla particular way of practicingtheJinvention, l do not wish to be underlStood as intending to limit itthereto, as various changes, alterations and modifications ,may be madenot only in the structure, but

also in the described method, without departing from the spirit of myinvention.

What l claim as new and desire to secure by Letters Patent is:

1. In the manufacture of forks for bicycles formed of a fork crown witha stem portion, the improvement which consists in shrinking a tubeforming the stem portion,

about a reenorcing-insert introduced into one end of the tube, insertingsuch end of the tube into the crown, and then brazing these partstogether.

2. In the manufacture of forks for bicytion, the improvement whichconsists in heating a. tube forming the stem portion, introducing areenforcing insert into the heated end of the tube, inserting such endlof the tube intothe crown `of the fork, and then brazing the partstogether.v y l 43. In a bicycle fork, a fork crown, atube extending atone en'd into the openingin said crown andv brazed therein, Vand aAreenforcing `insert in saidA end of the tube. with said tube shrunkabout the. insert to'provide a' `tight lit of said insert in said tubeand brazed in position therein. l.

4. 4In a bicycle fork, a fork crown containing an opening therethrough,a tube extendlng at one end into said opening and brazed therein, and areenforcing hollow insert secured in said tube and extending into saidcrown, said insert being'provided with a portion extending across itslower end.

' 5. In a bicycle fork, a fork crown, a'tube extending at one end intothe opening in said crown and brazed therein, and a reenforcing insertin said end of the tube with s aidtube shrunk about the insert toprovide a tight fit of said insert in said tube and brazed in po-'sition therein, the. wall of said insert being of .decreasing thicknessfrom 'its lower toward'its upper end.

ing an opening therethrough, a tube extending at one/,end into saidopening and brazed therein, anda reenforcing hollow insert secured'insaid tube and extending into said 6. ln a bicycle fork, a fork crowncontaincrown, said insert being provided with a portion extending'across its lower end, the wall of .said insert being of decreasingthickness from its lower toward its upper end.

7. ln a bicycle fork,v a forkcrown containing an opening therethrough, atube extending at one end-into -said opening and j brazed therein,l anda reinforcing. hollow insert in said end of the tube with said tubeshrunk about the insert to provide a tight fit of said insert in said"tube and i y brazed in position therein, said insert being provided witha portion extending across its lower end. l

GEORGE s. Lewis;

